PONDS. 25 



in the middle, and to diminish in depth towards both 

 ends, so as to grade off to nothing at the inlet and 

 outlet. Such ponds keep the cleanest. If the pond 

 is deep at the lower end, in the course of years a good 

 deal of refuse and unclean matter will collect there, 

 which you would rather have out of the pond, and 

 which would have naturally worked off at the outlet 

 if the bottom of the pond gradually shelved up to- 

 wards it. 



10. Always, if possible, have your ponds so ar- 

 ranged that you can draw off the water, if necessary. 

 When you want to make repairs or changes in the 

 pond, or wish to clean it out, this will be found a great 

 convenience ; but it is especially serviceable when you 

 want to use the pond for smaller fish than have been 

 living in it, for it is never quite safe to put small fish 

 in a pond which has been stocked with larger ones, 

 unless it is drawn off. 



Trout have such a wonderful faculty for getting out 

 of sight, that even in the best-constructed ponds, where 

 the water is not drawn off, they will often elude your 

 search, and one or two fish may still be left in the 

 pond after you have, as you believe, examined it thor- 

 oughly and taken them all out. I need not say how 

 mischievous the mistake would prove. Instances 

 could be cited of hosts of small fish having been de- 

 stroyed by one or two large ones, left unwittingly in the 

 pond. Therefore have your pond, if possible, so that 

 you can draw it off if required, and always do so when 

 you are going to substitute small fish for large ones 

 in it. 



